Remove visible fat from steak. Mix the cumin, chili powder and minced garlic together in a bowl. Rub onto both sides of steak.

Grill the steaks five to seven minutes for medium-rare, 145 degrees. Grill a few minutes longer for medium, 160 degrees. Or place on a baking sheet and broil eight to 10 inches from the heat for the same amount of time. Remove the steak from the grill and let rest on a carving board for five minutes.

Spray the onion and red bell pepper with olive oil spray. Place the vegetables over direct heat and close the lid of the grill. Cook the vegetables until they are tender, about eight to 10 minutes for the onions and six to eight minutes for the bell peppers. Wrap the tortillas in foil and place on the grill for two minutes to warm, turning once. The vegetables and tortillas can also be placed under the broiler. Watch to make sure they do not burn.

To serve, cut the steak against the grain into half-inch-thick slices. Place the warm tortillas, sliced meat, onions and peppers in separate serving dishes. Each person can make their own fajita by placing the fillings in the center of each tortilla.